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There is a lot of social concern that moles, sun exposure and skin cancer and how these factors interrelate with each other and how they influence each other.

First of all, let’s talk about nevi or melanocytic nevi or what in non-medical society are known as moles (we will use the term nevus for the scientific rigor of this blog). These lesions appear as a consequence of the proliferation of melanocytes, which are the cells responsible for coloring our skin. Therefore, these lesions can appear on any body area and are seen as brown to blackish-brown spots. The number of nevi can vary between tens and hundreds, being more numerous in people with low phototypes (redheads or blondes with green or blue eyes and who burn easily after sun exposure).

Most of these lesions are acquired, i.e., they appear from adolescence onwards and increase in number throughout adulthood. However, some lesions may be present at birth, in which case they are called congenital melanocytic nevi. It is these congenital nevi that are associated with a certain risk of degenerating to melanoma, which is directly related to the size of the lesions. This risk is assumed to be higher in giant congenital nevi or those larger than 20 cm in diameter.

Another group of lesions to be taken into account are the so-called dysplastic nevi or Clark nevi. They are nevi with their own entity as they usually have a certain irregularity both in their morphology (more irregular borders and large size) and in their chroma (irregular distribution of pigment with the appearance of various colors). The fact that these lesions present an increased risk of malignization is currently under discussion.

Applying these concepts to the review of these lesions, we as dermatologists recommend assessment in what we call the “population at risk for the development of melanoma”, which would include patients with multiple nevi (generally more than 50), patients with multiple dysplastic nevi, patients with congenital melanocytic nevi, especially if they are large, and patients with a history of familial melanoma.

Regarding sun exposure and the risk of developing melanoma skin cancer, after seeing hundreds of patients in my practice, I realize that there is a two-pronged approach to this issue. On the one hand, there are the skin cancer-obsessed patients who shun the sun and panic when a nevus changes morphology or size or causes itching. On the other hand, there are patients who are unaware of the existence of melanoma, sun worshippers who spend hours in the sun and who have never been evaluated by dermatologists, even though they belong to the risk group for the development of melanoma.

Applying the Aristotelian theory of the “right middle ground” and applying a little common sense, we must recognize the incorrectness of both extremes.
The sun is a source of energy that has beneficial properties for physical and mental health. People who consciously expose themselves to the sun have a more relaxed attitude towards life and even feel happier, according to some studies. Similarly, the sun has curative benefits against some inflammatory skin diseases such as psoriasis and atopic dermatitis and is a fundamental factor for the absorption of vitamin D, which the body needs for bone formation. However, irrational sun exposure can cause melanoma, especially in high-risk groups. That is, exposure to the sun without using a good sunscreen (SPF 50+) and during the hours of maximum radiation (between 12:00 and 17:00 hours).
Finally, a few words about skin cancer. Melanoma is a tumor resulting from the malignant transformation of melanocytes located primarily at the dermoepidermal junction and represents approximately 2.5-3% of existing cancers. The clinical features that suggest the diagnosis of melanoma can be summarized with the famous “ABCDE” rule:

-A: Asymmetry. The contour of one half is different from the opposite.
-B: Edges. They are irregular, blurred or uneven.
-C: Color. Heterogeneous coloration, including pink, brown, black, bluish, or whitish areas
-D: Diameter. They are usually larger than 6 cm.
-E: Evolution. Gross and uneven changes in recent months.

Therefore we try not to radicalize our positions towards the extreme of unfounded fear or absolute unconcern, let’s look for the virtue of the middle ground and take care of our skin, bearing in mind that it has a virtuous memory and that everything we take care of or neglect now, it will be able to reflect it in our future.